Effects of dauricine, quinidine, and sotalol on action potential duration of papillary muscles in vitro
Abstract
AIM: To compare the characteristics of dauricine, sotalol, and quinidine on
action potential duration (APD).
METHODS: Using intracellular microelectrode method to record APD in guinea pig
papillary muscles.
RESULTS: Dauricine 20 mumol.L-1 prolonged action potential at 90% repolarization,
the percent of APD prolongation were 22 +/- 8, 11 +/- 6, 9 +/- 5, 7 +/- 5, 6 +/-
3, 4.3 +/- 2.8, 4.5 +/- 2.8 at the cycle lengths of 200-2000 ms, dauricine became
more effective in lengthening APD at short cycle lengths. The effect of dauricine
on prolonging APD exhibited normal use-dependence, whereas quinidine 1 mumol.L-1
and sotalol 10 mumol.L-1 were less effective in lengthening APD at short cycle
lengths. The effect of quinidine and sotalol on APD exhibited reverse
use-dependence.
CONCLUSION: [corrected] The effect of dauricine on APD depends on activation
frequency.
Keywords:
action potential duration (APD).
METHODS: Using intracellular microelectrode method to record APD in guinea pig
papillary muscles.
RESULTS: Dauricine 20 mumol.L-1 prolonged action potential at 90% repolarization,
the percent of APD prolongation were 22 +/- 8, 11 +/- 6, 9 +/- 5, 7 +/- 5, 6 +/-
3, 4.3 +/- 2.8, 4.5 +/- 2.8 at the cycle lengths of 200-2000 ms, dauricine became
more effective in lengthening APD at short cycle lengths. The effect of dauricine
on prolonging APD exhibited normal use-dependence, whereas quinidine 1 mumol.L-1
and sotalol 10 mumol.L-1 were less effective in lengthening APD at short cycle
lengths. The effect of quinidine and sotalol on APD exhibited reverse
use-dependence.
CONCLUSION: [corrected] The effect of dauricine on APD depends on activation
frequency.